"Your client does not support opening this list with Windows Explorer"

Hi All,

I am getthing this strange issue when trying to open a document library with "Open with Explorer" option.  I am using Win7 with IE9.  First, I get prompted.  If I login, it will work fine until I restart the computer.  This is what I have done some far:

1. I have added the Sharepoint URL to the intranet site zone in IE
2. Follow the suggestions in http://support.microsoft.com/?id=943280 and http://support.microsoft.com/?id=841215
3. Restarted the WebClient services and even reboot

The result is that it work... but for a bried time.  Meaning, I can user the Open with Explorer to browse the library for a short period of time.  If I go away and comeback in a few minutes, I get the annoying "Your client does not support opening this list with Windows Explorer".

I am running out of ideas and need some help. Thanks guys.